Analysis of normal and abnormal amniotic fluid cells in vitro by cinemicrography

Clonal amniotic fluid-derived stem cells express characteristics of both mesenchymal and neural stem cells

Recent evidence has shown that amniotic fluid may be a novel source of fetal stem cells for therapeutic transplantation. We previously developed a two-stage culture protocol to isolate a population of amniotic fluid-derived mesenchymal stem cells (AFMSCs) from second-trimester amniocentesis. AFMSCs maintain the capacity to differentiate into multiple mesenchymal lineages and neuron-like cells. It is unclear whether amniotic fluid contains heterogeneous populations of stem cells or a subpopulation of primitive stem cells that are similar to marrow stromal cells showing the behavior of neural progenitors. In this study, we showed a subpopulation of amniotic fluid-derived stem cells (AF-SCs) at the single-cell level by limiting dilution. We found that NANOG- and POU5F1 (also known as OCT4)-expressing cells still existed in the expanded single cell-derived AF-SCs. Aside from the common mesenchymal characteristics, these clonal AF-SCs also exhibit multiple phenotypes of neural-derived cells such as NES, TUBB3, NEFH, NEUNA60, GALC, and GFAP expressions both before and after neural induction. Most importantly, HPLC analysis showed the evidence of dopamine release in the extract of dopaminergic-induced clonal AF-SCs. The results of this study suggest that besides being an easily accessible and expandable source of fetal stem cells, amniotic fluid will provide a promising source of neural progenitor cells that may be used in future cellular therapies for neurodegenerative diseases and nervous system injuries.

Hormone release by primary amniotic fluid cell cultures

Amniotic fluid cells have been widely used in prenatal diagnosis; however, there is great heterogeneity of the cells and their origin. In this study we analyze the karyotype and release of human chorionic gonadotropin (hCG), human chorionic somatomammotropin (hCS), free estriol (E 3), prolactin (PRL) and progesterone (P) of amniotic fluid cells from primary cultures of six normal and two anencephalic fetuses. In all the amniotic fluid samples there was release of hCG; in one amniotic fluid, in which several tetraploid colonies were found. PRL and P were also released. The heterogeneity of amniotic fluid cell morphology and their hormone release in culture was confirmed. The presence of hormones like hCG supports the trophoblastic origin of some amniotic fluid cells from normal and anencephalic fetuses. Other hormones, such as PRL and P could be used in the differential diagnosis between the karyotype of fetal membranes and the true fetal karyotype. Amniotic fluid cell cultures used in prenatal diagnosis yielded second trimester placental cells without any elaborate methods that could be used as cell models for hormone studies.

Amniotic fluid macrophages from normal and malformed fetuses

Amniotic fluid cells from normal and abnormal fetuses (neural tube defects and abdominal wall lesions) were examined uncultured and after short-term culture for macrophages. Morphology, adherence, phagocytosis, presence of Fc receptors and non-specific esterase were studied. The existence of macrophages in normal and abnormal fluids was confirmed, although the percentage and the absolute numbers varied greatly from specimen to specimen. The most marked increases in total macrophages were in cases of anencephaly. The significance of these macrophages and their value in prenatal diagnosis are discussed.